장소: 제1과학관 31214  e+첨단강의실 

초록: From the dynamical dielectric function of two-dimensional grapheme, which is calculated within the self-consistent-field approximation, we present the long-wavelength plasma oscillation (plasmon) in graphene layers, interacting via the long-range Coulomb interaction. Even though the plasmon in graphene has many desirable properties, including tunability via electrostatic gating and low loss, a combination of graphene layers effectively enhances the plasmonic resonance frequency and magnitude. We present the plasmon dispersion in multilayer graphene. The linear chiral gapless single-particle energy dispersion of graphene leads to plasmon properties with several unexpected experimentally observable characteristic features such as a nontrivial influence of an undoped layer on the multilayer plasmon dispersion and a strange influence from other layers even in the weak-coupling limit. Our predicted plasmon properties in multilayer graphene clearly distinguish graphene from the extensively studied usual parabolic 2D electron systems. We also present the collective excitations of coupled electron-phonon systems, taking into account the nonperturbative Coulomb coupling between electronic excitations in graphene and the substrate longitudinal-optical phonon modes. Our theoretical results provide the basis for the emerging and potentially far-reaching field of graphene plasmonics. The versatility of graphene means that graphene-based plasmonics may enable the manufacture of novel optical devices working in different frequency ranges, from terahertz to the visible, with extremely high speed, low driving voltage, low power consumption and compact sizes.